AKG K340 Bass Heavy Version

The AKG K340 is a one of a kind headphone produced by AKG that employs two drivers system: Electrostatic and Dynamic in one cans. This was a top-level cans back when it was produced. Selling for $300 in the 1980s. The headphone is highly innefficient, requiring only the most powerful kind of desktop headphone amplifiers, and definitely more suitable driven by a speaker amplifier. The now discontinued K340 had several versions while it was produced. The exterior is the same, but you will notice the difference once you plug in the headphones, and/or by dissecting the headphone and seeing the colour of the driver.

The K340 is one of the hardest headphones to drive, second only to the K1000. Ideally, you would plug these in to a speaker amp, but having experienced driving headphones with some speaker amps, I find that while powerful, they don’t have the refinement in sound that headphone amps have. Thus for this review we will stick to using the Beta 22 amplifier. On a gain 8 Beta 22 (Single ended), playing classical recordings out of a desktop CD Player, the volume is on 1 O’clock position. Quite heavy indeed.

If you know that this phone was sold at $300 in 1980, then you would immediately realize that in today’s money, it would outclass today’s top-of-the line AKG, the K701/K702. Indeed the K340 have highs, instrument separation, and speed that the K701 can only dream of. While the K701 is a regular open-design phone with dynamic driver, the K340 employs an electret driver for the high frequencies, a dynamic driver for the lower frequencies, and six passive radiator technology like in the K240 Sextett. I’ve listened to the K340 before, and I thought the sound is very thin and doesn’t offer much musicality. However for this review, I am listening to the Bass Heavy Version, and now that we have the bass back, we can start listening to music.

The K340 Bass Heavy Version is actually not a bassy phone, as the name might suggest. The reason that it is called Bass Heavy Version is because most K340s tend to be very light in their sound signature, lacking body and bottom frequency. The Bass Heavy Version, however, is what I would call a neutral phone. Something along the line of Sennheiser HD600 and Grado HP1000. It’s neutrality isn’t really everybody’s flavor, and people suggests pairing the K340 with tube amplifiers to add body and musicality. As amazed as I am listening to Beethoven’s Symphonies on the K340 & the Beta 22 amplifier, I know that Norah Jones isn’t going to work as well with this combination.

The high frequencies, coming out of the electret driver, trumps anything that the HD650, the K701, and the MS-Pro can produce. The strings section on an orchestra sounded sublime on the K340. Not only do you get speed and detail, but its treble is so refined without a hint of harshness and shrillness. Although the K340’s soundstage is nothing to brag about, it is instrument separation that really shines on the K340. No dynamic cans below the $1000 mark can touch the K340 on instrument separation.

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28 Comments

Barun Chanda

Hey Mike, Do you think that the LD MKIII amp (6H30p DR and WE403B) will be able to run the Bass heavy version of the AKG K340 ?… I might consider buying them if optimum sound levels can be achieved with the amp I just mentioned above…

Mike

Barun Chanda

If this helps…I can tell you that the amp can run the HE5 with the fiio e7 dac at 12-1 clock settings on the Mac Book Pro 2008 and 10-11 clock settings on a conventional windows PC with the creative sound blast sound card…

Mike

Edward

Mike, how can I tell specifically if I have the bass-heavy version of the K-340. I purchased mine back in 1982 or 1983 from J&R Music World (catalogue). The top of my headband is not imprinted in white lettering with "K-340". Although I've generally been happy with the quantity of the bass, it certainly takes a back seat to the upper mids and treble put out by the electrostatic driver. The bass is certainly less taut and well-defined as that on my Sennheiser HD-650's, or even my AKG K-701's, but the lower mids do match the richness of those put out by my HD-650's. All in all, based on my purchase date and the lack to the graphics imprint on the headband, I would surmise that my pair is one of the earlier sets produced. And such, is likely not a bass-heavy version. Anyway, how can I tell for sure which version I have??

Edward

When I said that the bass "certainly takes a back seat to the upper mids and treble" I didn't mean that it was reticent or insufficient in quantity; rather, I meant that the overall quality of the bass (precision, tautness, speed) provided by the dynamic driver could not match the overall quality of the upper mids and treble offered up by the electrostatic driver. Indeed, in my pair, bass quantity is "there", but I would definitely describe it as flabby and slow. Perhaps, then, I might have a bass-heavy pair.

Anonymous

Edward

Mike, did you have a chance to talk to your friend about indentifying the K340 bass-heavy version vs. the bass-light version? I apologize for beating a dead horse, but I’d really like to know this info for my own edification. Thanks again!!

Anonymous

Anonymous

Hi Edward, Sorry for sort-of-neglecting this issue earlier. I asked him just now. Basically you have to open the housing, and there you should find a plastic for driver protection. If the plastic color is green, then its bass-light. If the plastic color is grey, then it’s bass-heavy.

Edward

Anonymous

Edward

Mike, Thanks for being such a good sport with this. I promise I won’t hound you any more on this topic. As of now, I am debating whether to purchase a new Audez’e LCD-2, or wait for the LCD-3. Thanks again!

February 18, 2011

Anonymous

Not a problem, Edward. Hope that info I gave you is useful, cause I personally have never dismantled an AKG K340.

Edward

P.S. I recently downloaded the service guide (about 6 pages or so) for the K-340 from the AKG website. It mentions that there is a resistor that was removed in later models. Would this have anything to do with an increase in the bass output? And, if so, would the presence or lack of this resistor be a tell-tale indicator for whether a particular set of K-340's is a "bass-shy" or "bass-heavy" version?

Mike

Well, the resistor can account for something. Although normally if you want a bassier sound on regular dynamic headphones, you add a resistor, but I'm not so sure about the K340 circuitry.

My friend who compared the K340s said that the driver has a different color between the bass shy and bass heavy. But outside, there is no way to tell, so it's hard to judge the headphones just from pictures (say if you're hunting down a certain version).

I don't know, I'd just get a true electrostats or one of the modern orthos rather than the K340.

Anonymous

pcourtney1

Larry at Headphile sees a lot of K340 cans, and he does not think there are any different versions, not bass light or bass heavy, so I would take it all with a pinch of salt, it could be you need new pads or better clamping if you think they are “bass light”

I’ve had 5 different K340’s that I have listened to over the years, and still have 2 in my possession, and using the Musical Fidelity X-CAN V2 amp, it easily drives the K340 at the 12 0’clock position on the volume pot, you can also terminate the K340 cables to 4 speaker leads and connect to the speaker terminals on any decent amplifier, yes they are 400 ohms rated, so should be used with a nice headphone amp IMHO

Anonymous

pcourtney1

I know, I have heard many differences too with stock K340’s over the years (30 years) – but the curious thing is that if you modify all three different (allegedly) types of K340, the Green driver (Bass Light version) , Grey (Bass Heavy) and the Black ( Neutral or Balanced as some people say) , and you do the same mods on all three phones to the letter, they all sound remarkably similar to each other, in fact nearly impossible to distinguish between them in ABX testing. The you do some bass sweeps down to 20Hz, and guess what. all the K340’s I have experimented with drop off at 20Hz

pcourtney1

you are right that what is needed to drive a pair of K340’s is a decent HA, they do need a fair bit of current to really sound their best, and lots of voltage swing is required 🙂

Because the K340’s need a good amount of voltage to sound their best, many owners now re-cable them up as as balanced headphones, and this really helps to deliver the power they need. When given enough power they are very good IMHO, but balanced XLR headphone amps are not cheap, but they are probably the right pairing for these wonderful cans !

Steve B

I am listening to the Bass-Heavy K340’s via a Little Dot Mkiii right now, and the combo is sublime. I like it as much as the HiFiMan phones via my Woo Audio amp. The Little Dot’s OTL design loves the 400 ohm impedance. Just be sure to experiment a bit with the driver tubes and output tubes on the LD amp.